Tomchik Seth M, Davis Ronald L
Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
Neuron. 2009 Nov 25;64(4):510-21. doi: 10.1016/j.neuron.2009.09.029.
Functional imaging with genetically encoded calcium and cAMP reporters was used to examine the signal integration underlying learning in Drosophila. Dopamine and octopamine modulated intracellular cAMP in spatially distinct patterns in mushroom body neurons. Pairing of neuronal depolarization with subsequent dopamine application revealed a synergistic increase in cAMP in the mushroom body lobes, which was dependent on the rutabaga adenylyl cyclase. This synergy was restricted to the axons of mushroom body neurons, and occurred only following forward pairing with time intervals similar to those required for behavioral conditioning. In contrast, forward pairing of neuronal depolarization and octopamine produced a subadditive effect on cAMP. Finally, elevating intracellular cAMP facilitated calcium transients in mushroom body neurons, suggesting that cAMP elevation is sufficient to induce presynaptic plasticity. These data suggest that rutabaga functions as a coincidence detector in an intact neuronal circuit, with dopamine and octopamine bidirectionally influencing the generation of cAMP.
利用基因编码的钙和环磷酸腺苷（cAMP）报告基因进行功能成像，以研究果蝇学习过程中的信号整合。多巴胺和章鱼胺以空间上不同的模式调节蘑菇体神经元内的cAMP。神经元去极化与随后的多巴胺应用配对，揭示了蘑菇体叶中cAMP的协同增加，这依赖于rutabaga腺苷酸环化酶。这种协同作用仅限于蘑菇体神经元的轴突，并且仅在与行为条件作用所需的时间间隔相似的正向配对后发生。相比之下，神经元去极化和章鱼胺的正向配对对cAMP产生了次加性效应。最后，提高细胞内cAMP促进了蘑菇体神经元中的钙瞬变，表明cAMP升高足以诱导突触前可塑性。这些数据表明，rutabaga在完整的神经元回路中作为一个巧合探测器发挥作用，多巴胺和章鱼胺双向影响cAMP的产生。
